The Andromeda Galaxy

A neighbouring galaxy to our own Milky Way, the Andromeda Galaxy is 2.5 million light-years from Earth and contains in the region of one trillion stars.

Version 2: November 2022

I wanted a broadband target to test my new Askar 130PHQ (review here), and the Andromeda Galaxy was well-placed in the sky so won the contest. Shooting at 1000mm means that the field of view is narrower than I’m used to, but I quite like the unusual framing. Maybe I’ll make a mosaic in the future to capture the whole target.

The total integration time here is just 10 hours. This is much less than I normally go for, and to be honest I was expecting to need more data, but was curious to see what I could achieve with 10 hours so went ahead with processing. The end result was so good that I decided to declare it finished. (This also frees me up for my next project, which is testing the new Askar OIII+SII filter, review here).

I binned the data x2 to achieve a good working resolution, which gave a boost to the signal-to-noise ratio. This lowered the image’s overall resolution which, after a slight crop, is 3080×2056 — still plenty for zooming in to see more detail, or making large prints. I’m actually impressed at how fast I can collect data with this set-up, even ignoring the binning aspect. Slide along the image below to compare two raw stacks, both binx1: on the left is 24 hours of data with the Askar FRA400 (F/5.6) and on the right is 10 hours with the Askar 130PHQ (F/7.7).

Despite being under half the integration time, and a slower F/7.7, I think that the Askar 130PHQ has done a fine job.

* November 2022
* Bristol, UK (Bortle 8)
* Telescope: Askar 130PHQ Flatfield Astrograph
* Camera: ZWO ASI 2600MC-PRO
* Filter: None
* Mount: Sky-Watcher EQ6-R PRO
* Guide: William Optics 50mm Guidescope with 1.25″ RotoLock; ZWO ASI 120MM Mini
* Control: ASIAIR Plus
* Software: PixInsight, Lightroom
* 300 x 120 seconds

Total integration time: 10 hours

By Lee Pullen

Example source data

This is what a single 120-second subframe looks like, debayered and with a simple stretch.
This is the integration of 720 x 120 seconds (24 hours) just with a simple stretch, before any proper editing.

This image was used in the Winter 2023/24 issue of community magazine Up Our Street.

Version 1: September and October 2021

The Andromeda Galaxy is a highlight for astroimagers in the northern hemisphere. It’s nice and bright, and fits the field of view of my telescope and astrocamera well too, so hardly any cropping was required. Being a galaxy it’s a broadband target, so I left my faithful L-eXtreme out of the imaging train and got imaging without any filter.

24 hours of data went into the final integration. This was enough to combat Bristol’s light pollution and allow me to get a decent signal-to-noise ratio. The noise levels were low enough that I only performed a mild pass with Topaz DeNoise AI.

Still, it was tough to edit. Keeping things sharp but reasonably natural-looking is a balancing act I find tricky. And the galaxy’s core was a headache, causing me to restart editing a few times. I initially tried keeping the core very carefully controlled, i.e. quite dim. But sometimes I’d mess this stage up and end up with bright glowing core. I actually preferred this, so kept it in for this final version.

I noticed some dust spots on the final integrated image. I take one set of Flats per imaging project, which is normally fine, but I guess in this case some dust landed on the sensor before or after I took the Flats. I was scratching my head about how to fix this, but in the end the solution was easy: when editing in PixInsight, I routinely use StarNet to make a starless version to edit, before adding the stars back in. It was really easy to clone out the dust spots in the starless version.

I’d like to return to this target in the future, perhaps adding in some L-eXtreme data to reveal the glowing cloudy of hydrogen gas that are in the galaxy’s spiral arms. Sound like a project for next year.

Fun fact: all the individual stars visible in the image are within our own galaxy, and so are just a tiny fraction of the distance to the Andromeda Galaxy. They just happen to lie along the same line-of-sight. If you were to blast away in a futuristic spaceship and photograph the Andromeda Galaxy from intergalactic space, it would look more like this:

* September & October 2021
* Bristol, UK (Bortle 8)
* Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph
* Camera: ZWO ASI 2600MC-PRO (no filter)
* Mount: Orion Sirius EQ-G
* Guide: William Optics 32mm; ZWO ASI 120MM Mini
* Software: PixInsight, Photoshop, Topaz DeNoise AI, Lightroom
* Control: ASIAIR Plus; ZWO EAF
* 720 x 120 seconds

Total integration time: 24 hours

By Lee Pullen

Example source data

This is what a single 120-second subframe looks like, debayered and with a simple stretch.

This is the integration of 720 x 120 seconds (24 hours) just with a simple stretch, before any proper editing.

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5 thoughts on “The Andromeda Galaxy

  1. Mark Fowler says:

    Nice picture of our nearest galaxy. I’ve got a plus in the way. I currently use Nina with a very similar setup to yours so will be interesting to compare. Just a question on the power cable setup your using. What’s the plastic surround on the jack plug and does this eleaviate the strain on the socket. I ask this because I own the Pegasus power box that has the same setup which failed and consider this to be a weak point. Happy imaging, God give me clear skies.😁

    Reply
      1. Ryan Parle says:

        That plastic surround is a high shrink ratio (3:1 or 4:1) adhesive lined heatshrink that is used to provide better strain relief, it can be added to many types of connector as a modification, you can simply cut a length that covers the connector body and a section of the wire, slide it on and heat with a hot air gun (or carefully with a lighter).

        Reply

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